Diacyl-hydrazine stabilizers for polyolefins

ABSTRACT

Disclosed are process for stabilising polyolefines with compounds of formula 1, use of compounds of formula 1 for stabilising polyolefines and stabilising compositions, comprising; A. A POLYOLEFINE; AND B. COMPOUNDS OF THE FORMULA

United States Patent Rosenberger et al.

[451 May 20, 1975 1 i DlACYL-HYDRAZINE STABILIZERS FOR POLYOLEFINSInventors: Siegfried Rosenberger, Richen;

Andreas Schmidt, Reinach, both of Switzerland Ciba-Geigy Corporation,Ardsley, N.Y.

Filed: Nov. 16, 1972 Appl. No.: 307,269

Assignee:

[30] Foreign Application Priority Date References Cited UNITED STATESPATENTS 10/1957 Bell et al. 260/459 NC 2/1962 Armitage et al. 260/459 NC5/1962 Spacht 260/459 NC 5/1972 Dexter 260/459 NC 11/1973 Dexter 260/459NC Primary Examiner-V. P. Hoke Attorney, Agent, or Firm-Nestor W. Shust;Luther A. R. Hall {57] ABSTRACT Disclosed are process for stabilisingpolyolefines with compounds of formula 1, use of compounds of formula lfor stabilising polyolefines and stabilising compositions, comprising;

a. a polyolefine; and

b. compounds of the formula R,-CO-NHNH--COR,

in which R, and R, independently of one another dcnote the unsubstitutedphenyl group, a phenyl group substituted by a hydroxyl group in the morpposition, by one or two alkyl groups each with l to 4 carbon atoms, byone or two alkenyl groups each with 3 or 4 carbon atoms by one or twocycloalkyl groups each with 6 to 8 carbon atoms, by one or two chlon'neatoms, by one or two alkoxy groups each with i to 18 carbon atoms, byone or two acyloxy groups each with 2 to 18 carbon atoms, by anacylamino group with 2 to 18 carbon" atoms or by an amino group in theoposition, or a pyridyl radical or in which, if R, denotes a substitutedphenyl group, R, also denotes hydrogen, alkyl with i to 18 carbon atoms,cyclohexyl or benzyl. Also disclosed is a process for the manufacture ofnovel compounds of the formula l, in which R and R independently of oneanother" denote phenyl groups which are substituted in the mor ppositionby a hydroxyl group or one or 2 alkoxy groups with l to 18 carbon atoms,and in which R, also denotes an alkyl group with l to 18 carbon atoms,cyclohexyl, benzyl or phenyl.

13 Claims, No Drawings DlACYL-HYDRAZINE STABILIZERS FOR POLYOLEFINS Thesubject of thepresent newdiac'ylhydrazines and their-use forstabilising'polyolefines.

able for use as an insulating materialwith transitionmetals,especiallywithcoppcr and its compounds, the polyolefines undergoan oxidative degradation catalysed by these metals. Additions of copperof less than l percent for example already lead to-the degradation andat the same time possess good colour 7 properties. a f 1 The compoundsof the formula I in particular protect homopolymeric'and copolymericpolyolefines against ",thermooxidative degradation in the presence oftransition metals.' 1.1 3 f f.-- "1;Th e compounds'pfthe formula] arenot only excel- ;lent stabiiisersbut furtherrnorehave the advantage ofbeingcolourlessq-Thismakc s itpossible to incorporate ,them intopolyolefines withoutobjectionably discolourfing the:- latter. All fthe'abovementioned previously 1 known corripou'nds have theproperty. ofhaving a disstability of polypropyleneflto oxidationjbeing reduced by afactor of -l00. g E 7 Various different acylationf products of hydrazinehave already been disclosed for stabilising polyolefines against theharmful action of transition metals, such as, for example, alkylat'ed,'cycloalkylated, arylated or acetylated derivatives of salicylic acidhydrazide; dihydrazides of various dicarboxylic acids,fand alsoacylation products of hydrazine with acids containing sulphur. a

All these compounds show certain technical disadvantages. On the onehand, their activity is'ins'ufficient completely to suppress the harmfulaction of the transition metal. On the other hand, they objectionablydiscolour the polyolefine either alreadyywhilst being incorporatcd orunder thermobxidative aging-conditions. The latter disadvantage, inparticular, manifests itself in the case of other classes of activedicarbo tylic acid dihydrazide derivatives which have been disclosed,namely in the case of the bis-arylidenedicarboxylic acid dihydrazides, mthe case of the bisalkylhydroxyphenylalkanoyl-hydrazin es and in thecase of the bis-aikylhydroxybenzoyl-hydrazines. Whilst these display asatisfactory deactivating action, they are in themselves alreadyyellow-coloured compounds. None of the types of compound hithertodisclosed combincs in itself the technically desired optimum stabilisingaction with absence of colour under use conditions.

it has now been found that the compounds of the formula l in which R,and R, independently of one another denote the unsubstituted phenylgroup, a phenyl group substituted by a hydroxyl group in the morp-position, by one or two alkyl groups each with l to 4 carbon atoms, byone or two alkenyl groups each with 3 or 4 carbon atoms, by one or twocycloalkyl groups each with 6 to 8 carbon atoms, by one or two chlorineatoms, by one or two alkoxy groups each with l to 18 carbon atoms, byone or two acyloxy groups each with 2 to l8 carbon atoms, by anacylamino group with 2 to 18 carbon atoms or by an amino group in theo-position, or a pyridyl radical or in which. if R, denotes asubstituted phenyl group. R, also denotes hydrogen, alkyl with l to l8carbon atoms, cyclohexyl or benzyl, are, surprisingly, very suitable forstabilising homopolymeric or copolymeric polyolefines againstthermo-oxidative acid, stearic acid, benzoic acid or phenylacetic acid.

colouring'cffect in polyolefines underaging conditions. whilst thecompounds according to the invention cause practically,no'discolouratlons under these conditions. which' rcpresentsagreattechnical advantage for longterm stabilisation.

g ;If andR, are phenyl groups substituted. by alkyl .groups with 11014carbon atoms each, the alkyl groups can be, methyl, ethyl,-propyl,iso-propyl, butyl, sec.

butyl,;or tert. butylsyAs alkenyl-substituted phenyl groups, R, and mm,for example, be allylphenyl or butenylphenyhlf the substituents of thephenyl groups R, and R, are: cyclohexyl groups each with 6 to 8 carbonatoms, these substituents can be cyclohexyl, or-rnethylcyclohexyl orcyclooctyL'lf R 'and R, denote phenyl groups substituted by alkoxygroups each with i to 8 carbon atoms, the alkoxy. groups can bemethoxy,

'ethoxy, p'ropoxy, iso-propoxy, butoxy, sec.'-butoxy, .;tert.-butoxy,pentoxy, tert. pentoxy, sec.-pentoxy, hexoxy, isoheptoxy, octoxy or l',l,3,3-tetramethylbutoxy,

undecyloxy, dodecyloxy, hexadecyloxy or octadecyloxy. R, and R, can alsobe phenyl radicals substituted by acyloxy or acylamino groups, each with2 to 18 carbon atoms, in which case acyl" can be, for example, the a'cylradical of the following acids: acetic acid, propionic acid, butyricacid, isobutyric acid, vale- 'ric acid, caproicacid, Z-ethylcaproieacid, caprylic acid, capric acid, lauric acid, myristic acid, palmiticThe preferred acyl radical is the radical of the benzoic acid. If R,denotes a'substituted phenyl group, R, can also be an alkyl group with lto 18 carbon atoms such as methyl, ethyl, propyl, butyl, pentyl, hexyl,iso-heptyi. octyl, nonyl, undeeyl, dodecyl, tetradecyl, hexadecyl oroctadecyl.

The preferred compounds of the formula I are those in which R, and R,independently of one another denote a phenyl group which is substitutedby a hydroxyl group in the mor p-position, by one or two alitoxy groupseach with l to 18, and particularly preferentially l to l6, carbonatoms, by an acylamino group with 2 to 7 carbon atoms or by an aminogroup in the oposition, or in which, if R, represents an acylaminophenylgroup with 2 to 7 carbon atoms in the acyl radical, R, also denotesalkyl with l to 8 carbon atoms and particularly preferentially methyl,benzyl or phenyl.

Compounds of the formula l in which R, and R, independently .ofoneanother denote phenyl groups which are substituted in the mor p-positionby a hydroxyl group or one or 2 alkoxy groups with l to l8, preferably lto l6, carbon atoms, and in which R, also denotes an alkyl group with lto l8 carbon atoms, cyclohexyl. benzyl or phenyl, are new.

The following are examples of compounds of the formula-l which displayparticularly good stabilising prop- 3 erties: N ,N '-bis-(3 ,5-dimethoxybenzoyl)-hydrazine, N ,N '-bis-(4-octyloxybenzoyD-hydrazine,N-(4- benzoylaminobenzoyl)-N'-benzoyl-hydrazine, N-(4-acetylaminobenzoyl)-N'-acetylhydrazine and N,N'-bis-(2-aminobenzoyl)-hydrazine.

The compounds of the formula I provide protection norbornene; mixturesof the abovementioned homo-'- polymers such as, for example, mixtures ofpolypropylene and polyethylene, polypropylene and poly-butene- 1, andpolypropylene and polyisobutylene. Polypropylene and its mixtures, andthe copolymers which contain propylene units, are preferred.

The compounds of the formula I are incorporated into the substrates in aconcentration of 0.01 to percent by weight relative to the material tobe stabilised.

Preferably, 0.05 to 1.5, and particularly preferably v0.1 to 0.8,percent by weight of the compounds, calculated relative to the materialto be stabilised, are incorporated into the latter. The incorporationcan be effected after polymerisation, for example by mixing at least oneof the compounds of the formula 1 and optionally further additives intothe melt in accordance with the methods usual in the art, before orduring shaping, or by applying the dissolved or dispersed compounds tothe polymer, if necessary with subsequent evaporation of the solvent.

in the case of crosslinked polyethylene, the compounds are added beforecrosslinking.

As further additives together with which the stabilisers usableaccording to the invention can be employed, there should be mentioned:

l. Anti-oxidants of the aminoaryl and hydroxyaryl series. Amongst thelatter, the sterically hindered phenol compounds should be mentioned,for example: 2,2- -thiobis-(4-methyl-6-tert.butylphenol), 4,4'-thiobis-(3-methyl-6-tert.butylphenol), 2,2'-methylene-bis-(4-mcthyl-6-tert.butylphenol), 2,2'-methylene-bis-(4-cthyl-6-tert.butylphenol), 4,4-methylene-bis-(2-methyl-6-tert.butylphenol), 4,4'-butylidene-bis-(3-mcthyl-6-tert.butylphenol), 2,2-methylene-bis-[4-methyl-6-(a-methylcyclohexyl)-phenol], 2,6-di-(2-hydroxy-3-tert.butyl-$-methylbenzyl)-4-methylphenol,2,o-di-tert.butyI-4-methylphenol, l, l ,3-tris-( Z-methyl-4-hydroxy-S-tert.butyl-phenyl)-butane, 1,3,5-trimethyl-2,4,6-tri-(3,5-di-tert.butyl-4-hydroxybenzyl)- benzene, estersof fi-4-hydroxy-3,5-di-tert.butylphenylpropionic acid with monohydric orpolyhydric alcohols, such as methanol, ethanol, octadecanol, hexanediol,nonanediol, thiodiethylene glycol, trimethylolethane or pentaerythritol,or tris-hydroxycthylisocyanurate, 2,4-bis-octylmercapto-6-(4-hydroxy-3,5-di-tert.butylanilino)-s-triazine, 2,4-bis-(4-hydroxy-3,5-di-tert.butylphenoxy)-6-octylmercapto-striazine, l, 1 -bis-(4-hydroxy-Z-methyl-5-tert.butylphenyl)-3-dodecyl-mercapto-butane,4-hydroxy-3,5- di-tert.butylbenzyl-phosphonic acid esters, such as thetrioxabicyclo-l2,2,2]-octane 3 (3,$-ditert.butyl-4-hydroxyphenyl)-propionate, l,3,5-tris-( 3,5-

=dite rt.butyl-4-hydroxybenzyl)-isocyanurate and 1,3,5-

- tris'-(3-[3,5-ditert.butyl-4-hydroxyphenyll-propionyl)-hexahydro-s-triazine. I

Amongst the aminoaryl derivatives there should be mentioned anilineandnaphthylamine derivatives as well as their heterocyclicderivatives,for example: phenyl-l-naphthylarnine, phenyl-Z-naphthylamine, N,-N'diphenyl-p-phenylenediamine, N,N'-di-2-naphthylp-phenylenediamine," IN,N'-di-sec.butyl-pphenylenediamine, 6-ethoxy-2,2,4-trimethyli ,2-dihydroquinoline, 6-dodecyl-2,2,4-trimethyl-l ,2- hydroquinoline,monoand di-octyliminodibenzyl and polymerised 2,2,4-trimethyll,2-dihydroquinoline, though in the case of the combined use of thecompounds of the formula I with the abovementioned amine compounds thestabilised polymer no longer has such good colour properties, because ofthe tendency to discolouration of the amine compounds.

2. UV-absorbers and light protection agents such as:

a. 2-(ZHydroxyphenyl)-benztriazoles, for example the 5'-methyl-;3',5'-di-tert.butyl-; 5'-tert.butyl-; 5- chloro-S; 5'-di-tert.butyl-;5-chloro-3'-tert.butyl-5'- methyl 3',$ '-di-tert.amyl-;3'-methyl-$'-B-methoxycarbonylethyb', and5-chloro-3,S'-di-tert.amylderivative.

b. 2,4-Bis-(2-hydroxyphenyl)-6-alkyl-s-triazines, for

example the 6-ethylor o-undecyl-derivative.

c. Z-Hydroxy-benzophenones, for example the 4- hydroxy-, 4-methoxy-,4-octoxy-, 4-decyloxy-, 4- dodecyloxy-4,2',4tri-hydroxyor2'-hydroxy-4,4'- dimethoxy derivative.

d. i,3-Bis-(2'-hydroxy-benzoyl)-benzenes, for example l,3-bis-(2'-hydroxy-4'-hexyloxy-benzoyl)-benzene,l,3-bis-(2'-hydroxy-4'-octoxy-benzoyl)-benzene and l ,3-bis-(2'-hydroxy-4'-dodecyloxy-benzoyl benzene.

e. Aryl esters of optionally substituted benzoic acids such as, forexample, phenyl salicylate, octylphenyl salicylate, benzoylresorcinol,dibenzoylresorcinol, 3,5-di-tert.butyl-4-hydroxybenzoic acid2,4-di-tert- .butyl-phenyl ester or octadecyl ester.

1'. Acrylates, for example a-cyano-B,B,-diphenylacrylic acid ethyl esteror isooctyl ester, a-carbomethoxycinnamic acid methyl ester,a-eyano-B-methyl-pmethoxy-cinnamic acid methyl ester or butyl ester andN-(B-carbomethoxyvinyl)-2-methylindoline.

g. Nickel compounds, for example nickel complexes of bis-[2-hydroxy-5-(l l ',3',3-tetramethylbutyl phenyl1sulphide, such as the 1:1- andlz2-complex, optionally with other ligands such as n-butylamine; nickelcomplexes of bis-[2-hydroxy-5-(l',l',3',3'-tetramethylbutyl)phenyllsulphone, such as the 2:]- complex, optionallywith other ligands such as 2- ethylcaproic acid; nickeldibutyldithiocarbamate, nickel salts or4-hydroxy-3,5-di-tert.butyibenzylphosphonic acid monoalkyl esters, suchas the methyl, ethyl or butylester, and the nickel complex of2-hydroxy-4-methyl-phenyl-undecylketonoxime.

h. Oxalic acid diamides, for example 4,4'-dioctyloxyoxanilide, 2,2'-di-octyloxy -5,5 ditert.butyloxanilide and2,2-di-dodecyloxy-5,$'-di-tert.butyloxanilide.

3. Phosphites, such as triphenylphosphite, diphenylalkylphosphites,phenyldialkylphosphites, trionylphenylphosphite, trilaurylphosphite,trioctadecylphosphite, 3 ,9-di-isodecyloxy-2,4,8 l 0-tetraoxa-3,9-diphosphaspiro-(5,5)-undecane and tri-(4-hydroxy-3,5di-tert.butylphenyl)-phosphite.

4. Nucleating agents, such as 4-tert.butylbenzoic acid, adipic acid anddiphenylacetic acid.

5. Compounds which destroy peroxides, such as esters ofB-thiodipropionic acid, for example the lauryl, stearyl, myristyl or:tridecyl ester. Salts of .2- mercaptobenzimidazole, for example the zincsalt, and diphenylthiourea.

6. Other additives such as plasticisers, anti-static agents, dyeingauxiliaries, flameproofing agents, pigments, carbon black, asbestos,glass fibres, kaolin, talc and blowing agents.

When using the stabilisers according to the invention in combinationwith phenolic anti-oxidants, particularly good stabilising effects areachieved if at the same time compounds which destroy peroxides, such ashigher alkyl esters of thiodipropionic acid, are employed, since thesecompounds which destroy peroxides not only show synergism, as is known,with the phenolic anti-oxidants, but also show synergism with thestabilisers of the formula I.

The compounds of the formula I can above all be manufactured by tworeaction paths which are in themselves known:

a. Reaction of 2 mols of a substituted benzoic acid chloride with onemol of hydrazine, whilst adding 2 mols of alkali hydroxide. Thisreaction path yields symmetrical substituted dibenzoyl hydrazines.

b. Reaction of a monocarboxylic acid hydrazide with a reactivederivative of a monocarboxylic acid, that is to say a monocarboxylicacid chloride or a monocarboxylic acid anhydride. in some case,monocarboxylic acid esters can also be used.

The polyolefines stabilised by addition of the compounds according totheginve'ntion are, in particular, suitable for use as coatingmaterialsof copper wires and cables, but also forothertypes of metal coating andfor the manufacture of shaped articles, such as films, filaments,sheets, pipes, injection moulding articles and the like, Theyi can alsobe used mixed with copper or with pigments containing copper.

'The invention is explained in more detail in the exampleswhich follow.

' EXAMPLE 1 l2 3 (0.3 mol) of sodium hydroxide and 7.5 g (0.15 mol) ofhydrazine hydrate are initially introduced into 350 ml of water. Thesolution is treated dropwise, at room temperature, with g (0.3 mol) of3,5-dimethoxybenzoyl chloride. When the slightly exothermic reaction hassubsided, the mixture is stirred for a further 12 hours. The product isfiltered off and recrystallised from methanol. TheN,N'-bis-(3,5-dimethoxybenzoyl)-hydrazine thus obtained (StabiliserNo.1) has a melting point of 194C.

If in this example the 3,5-dimethoxylbenzoyl chloride is replaced by anequimolecular amount of one of the benzoic acid chlorides of Table lwhich follows, and otherwise the same procedure is employed, theN,N'-dibenzoylhydrazines having the indicated melting points areobtained.

Table 1 Formula of the bensoic Belting point or the o iieerystalliuedacid chloride N,N'-dibensoy1hydrasine in 0 Iron Acetone- 87 (BtabilisorNo.2)

.(smnm: No.4)

265 (Stabilieer no.5)

237 (stabilise: no.1)

157-1511 (Bte'bilieer um) 333-}38(Stabil1sor no.5)

Ethylene glycol aonoacthyl ether 7 EXAMPLE 2 @co-mmn co 15.2 g (0.1 mol)of 3-hydroxybenzoic acid methyl ester and 15.2 g-(0.l mol) ofS-hydroxybenzoic acid hydrazidc together with 500 mg of lithium amideare fused at 150-l60C. After a short time, the reaction mixture againsolidifies. After 1 hour, ml of tetralin are added and the mixture isstirred for a further hour at 160C. After cooling, 200 ml of methanolare added and the mixture is briefly stirred up and the'product isfiltered off. For purification, the product is dissolved in a littledimethylforrnamide and reprecipitated with alcohol.N,N'-Bis-(3-hydroxybenzoyl)-hydrazine (Stabiliser No.8) of melting point319C is thus obtained.

if in this example the S-hydroxybenzoic acid methyl ester and theB-hydroxybenzoic acid hydrazide are replaced by equimolecular amounts of4-tert.butylbenzoic acid methyl ester and 4-tert.butylbenzoic acidhydrazide, and otherwise an analogous procedure is followed,N,N'-bis-(4-tert.butylbenzoyl)-hydrazine (Stabiliser No.9) of meltingpoint 285C is obtained.

if in this example the 3-hydroxybenzoic acid methyl ester and theS-hydroxybenzoic acid hydrazide are replaced by equimolecular amounts of4-hydroxybenzoic acid methyl ester or 4-hydroxybenzoic acid hydrazideand otherwise the same procedure is followed, N,N'-bis-(4-hydroxybenzoyl)-hydrazine of melting point above 300C isobtained.

EXAMPLE 3 @CONH CO-NHNHCO 12.1 g (0.08 mol) of 4-aminobenzhydrazide aredissolved in 60 ml of dimethylacetamide. A solution of 22.5 g (0.16 mol)of benzoyl chloride in ml of dioxane is added dropwise to this solutionat room temperature. The reaction takes place with evolution of heat.Thereafter the mixture is kept for 2 hours at 90C, cooled and pouredinto 500 ml of water, whereupon the reaction product precipitates. Thesubstance is filtered off. washed with alcohol and purified byrecrystallisation from ethylene glycol monomethyl ether. The N-4-benzoylaminobenzoyl )-N -benzoyl-hydrazine thus obtained (StabiliserNo.10) melts at 264C.

if in this example the benzoyl chloride is replaced by an equivalentamount of acetyl chloride or acetic anhydride and otherwise an analogousprocedure is followed, N-(4-acetylaminobenzoyl)-N'-acetyl-hydrazine(Stabiliser No.1 1) is obtained, which after crystallisation from 90percent strength alcohol melts at 286C.

1f the 4-aminobenzhydrazide is replaced by an equivalent amount ofZ-aminobenzhydrazide and the reac-N-(2-benzoylarriinobenzoyl)-N'-benzoyl-hydrazine (Stabiliser No.l2)ofmelting point238C is obtained.

A v l A i A i t."

MH rm comnnco A warmed to 110C for l5 hours. After cooling the productis filtered off, washed with ligroin and repeatedly recrystallisedfromglacial acetic acid. N,N'-Bis-(2- aminobenzoyD-hydrazine (StabiliserNo. 13) of melting point 207C is thus obtained.

EXAMPLE 5 Q-commnco c1 7.1 g (0.05 mol) of cyclohexanecarboxylic acidhydrazide are dissolved in ml of dimethylacetamide at 50C. A solution of8.8 g (0.05 mol) of 3-chlorobenzoyl chloride in 50 ml ofdimethylacetamide is slowly added dropwise at this temperature.Thereafter the yellow so- ,..lution is mixed with 5.0 g of triethylamineand stirred for 1 hour at 50C. After cooling, the mixture is poured into1 litre of water and the product which has precipitated is filtered offand dried at C. After recrystallisation from methylcellosolve, the N-(3-chlorobenzoyD-N'-cyclohexanoyl-hydrazine thus obtained (StabiliserNo.l4) shows a melting point of above 240C.

@COMNHCO/ p? 13.7 g (0.] mol) of picolinic acid hydrazide are dissolvedin ml of dimethylacetamide. The yellow solution is mixed dropwise with asolution of i5 .5 g (0.1 1 mol) of picolinic acid chloride in 60 ml ofdimethylacetamide. The mixture turns almost black. After stirring for 1hour at 60C, it is poured into 1 litre of water, the resulting acidsuspension is neutralised with sodium carbonate and the product isfiltered off. After drying, it is repeatedly recrystallised fromethylene glycol monomethyl ether. The N.N-dipicoloyl-hydrazine thusobtained (Stabiliser No.l5) melts at 218C.

The previously known metal deactlvators for polyolefines listed in Table2 which follows were also tested as comparison compounds in the testexamples which follow.

Table 2 Stabiliser Chemical Name 16 N,N'-Bis-( l2-thia-tetracosanoyl)-hydrazine l7 Oxalic acid dihydrazide l 8 Carbohydrazide l9 Malonicacid dihydrazidc 20 Adipic acid dihydrazidc 2l Terephthalic aciddihydrazidc 22 lsophthalic acid dihydrazidc 23 Succinic ucidbis-phenylhydrazide 24 Sehacic acid his- 'nen lhydrazide 25 Salicylicacid hytii'azi c 26 N-Acetyl-N'salicyloyl-hydrazine 27N-Salicyloyl-N'-salicylal-hydrazine EXAMPLE 7 a. Manufacture of the testspecimens 100 parts by weight of polypropylene (melt index 3.2 g/ lminutes, 230C/2, l 60 g) are thoroughly mixed for 10 minutes, in ashaking apparatus, with 0.1 part'by weight of3-(3,S-di-tert.butyl-4-hydroxy-phenyl)- propionic acid octadecyl ester,0.3 part by weight of dilauryl thiodipropionate and 0.5 part by weightof one of the additives listed in Table 3 below.

The resulting mixture is kneaded for 10 minutes in a Brabenderplastograph at 200C, then mixed with 1.0 percent by weight of powderedcopper (manufactured electrolytically, Merck) and thoroughly mixed for afurther 2 minutes at the same temperature. The mass thus obtained issubsequently pressed in a sheet press at 260C platen temperature to give1 mm thick sheets from which strips l cm wide and I7 cm long arepunched.

The heat-stabilised test specimens without added copper, or with addedcopper but without metal deactivator, which are required for comparisonpurposes, are manufactured analogously.

b. Test The test of the activity of the 'inetal deactivators added tothe test strips containing copper is effected by heat aging in acirculating air oven at 149C and the result is compared with test stripsnot containing copper. For this purpose, 3 test strips of eachformulation are employed. The end point is defined as the incipienteasily visible decomposition of the test strip.

EXAMPLE 8 a. Manufacture of the test specimens 7 I00 parts'by'weight ofpolypropylene (melt index 3.2 g/lO minutes, 230C/2,l 60 g) arethoroughlymixed for l0 minutes;in?aflshakingapparatus, with 0.l part by weigh t of-"3 (-3,5 di-tei't.butyl54 hydroxy-phenyl propionic acid octadecyljester,'0.' 3 part bycweight of dilauryl thiodipropionateand 0.5 p'artby weight of one of the additives listed in Table "4 below.

The resulting mixture iskneaded for minutes in a 'Brabenderplastographat 200C. then-mixed with 1.0 percent by weight of powderedcopper (manufactured electrolytically, Merckiand thoroughly mixed for afurther 2 minutes at the same temperature. The mass thus obtained issubsequently pressed in a sheet press at 260C platen temperature to give1 mm thick sheets from. which strips 1" cm wide and 17 cm long arepunched by means of a punch tool.

The heat-stabili shed test specimens without added copper, or with addedcopper but without metal deacti' vator, which are required forcomparison purposes, are manufactured analogously.

b. Test g I r The 'test of the activity of the metal deactivators addedto the test strips containing copper is effected by heat aging in acirculating air oven at 135C and the result is compared with test stripsnot containing copper. For this purpose, 3 test strips of eachformulation are employed. The end point is defined as the incipienteasily visible decomposition of the test strip.

The test specimens without added copper, described in Example 7. areadditionally tested for their colour stability, namely:

a. after incorporation (Table 5, Column 2) b. after heat aging at l49C(Table. 5, Column 3) c. after treating for 1 week with boiling water(Table 5, Column 4).

An empirical colour scale was used for the table, in which 5 denotesabsence of colour 4 denotes a just perceptible slight discolouration and3,2,1 l denote progressively stronger discolouration.

Table Test for Colour Stability (without added copper) Stabiliser No.Colour Assessment according to scale l 5 after incorporation after heataging at 14913 boiling water, 1 week without 5 4 4 additive I 10 4 2 4-5l l 4 2 4 l3 4 l 3 l5 3 l 3 Comparison Products 23 3-4 1 2-3 24 l l l 25l I 1 26 l 2 1 27 1 1 2 EXAMPLE l0 EXAMPLE 11 100 parts by weight ofpolypropylene (melt index 3.2 gl] 0 minutes, 230C/2,l60 g) arethoroughly mixed for 10 minutes, in a shaking apparatus, with theadditives listed in Table 6, in the indicated concentrations.

The resulting mixture is kneaded for 10 minutes in a Brabenderplastograph at 200C, then 0.1 percent by weight of copper stearate isadded and the whole is thoroughly mixed at the same temperature for afurther 2 minutes. The mass thus obtained is subsequently pressed in asheet press at 260C platen temperature to give 1 mm thick sheets fromwhich strips 1 cm wide and 17 cm long are punched by means of a punchThe fully stabilised test specimens without added copper stearate,required for comparison purposes, are manufactured analogously.

The activity of the metal deactivator (stabiliser No. l0) in the teststrips containing copper stearate is tested by heat aging in acirculating air oven at 149'C. For results, see Table 6, column 4. Theoven aging times of the test specimens without added copper stearate,required for comparison. are given in Table 6, column 3.

" uns by wei ht calculated relative to the unltabillasd polypropylene.

Additives Used:

A: 1.1.3-Tris-(3'-tert.-butyi-4'-hydroxy-6'-methylphcnyl)-butane B:Dilaurylthiodipropionate 100 parts by weight of polypropylene (meltindex 3.2 g/lO minutes, 230C/2,l60 g) are thoroughly mixed in a shakingapparatus with 0.1 part by weight of 3-(3 ,5'-di-tert.-butyl-4-hydroxyphenyl)-propionic acid octa- 30 decyl ester, 0.3part by weight of dilaurylthiodipropionate and one of the additiveslisted in Table 7 below, in the indicated amount.

The resulting mixture is kneaded for 10 minutes in a Brabenderplastograph at 200C, then mixed with 1.0

percent by weight of powdered copper (manufactured electrolytically,Merck) and thoroughly mixed for a further 2 minutes at the sametemperature. The resulting mass is subsequently pressed in a sheet pressat 260C platen temperature to give 1 mm thick sheets from which strips 1cm wide and 17 cm long are punched with the aid of a punch tool.

The test 01' the activity of the metal deactivators added to the teststrips, as a function of the concentration, is carried out by heat agingin a circulating air oven at 149C. The results are indicated in Table 7.

"pens by weight calculated relative to the unstablliaed polypropylene.

EXAMPLE 12 parts by weight of polypropylene (melt index 3.2 g/l0minutes, 230C/2,l60 g) are thoroughly mixed for 10 minutes in a shakingapparatus with 0.1 part by 5 weight of one of the additives listed inTable 8 below and 0.3 part by weight of dilaurylthiodipropionate.

The resulting mixture is kneaded for 10 minutes in a Brabenderplastograph at 200C and the mass thus obtained is subsequently pressedin a sheet press at 260C platen temperature to give 1mm thick sheetsfrom which strips l cm wide and l7 cm long are punched.

The test of the activity of the additives added to the test strips, asregards their property as synergisticaliy acting antioxidants in thepresence-of dilaurylthiodipropionate, is carried out by heat aging in acirculating air oven at l35C and 149C, with an additive-free test stripserving for comparison. For this test, 3 test strips of each formulationare employed. The incipient easily visible decomposition of the teststrip is defined as the end point; the results are indicated in days.

100 parts by weight of polypropylene (melt index 3.2 g/ l minutes,230C/2,l60 g) are thoroughly mixed for minutes in a shaking apparatuswith 0. lpart by weight of 3-(3,5 di-tert.-butyl-4-hydroxyphenyl)-propionic acid octadecyl ester (Additive C), 0.3 part by weight ofdiiaurylthiodipropionate (Additive B) and 0.5 part by weight of anadditive listed in Table 9 below.

The resulting mixture is kneaded for 10 minutes in a Brabenderplastograph at 200C and the mass thus obtained is subsequently pressedin a sheet press at 260C platen temperature to give I mm thick sheetsfrom which strips l cm wide and 17 cm long are punched.

The test of the activity of the additives added to the test strips, inrespect of their property as synergisticaliy acting antioxidants in thepresence of additives C and B. is carried out by heat aging in acirculating air oven at 135C and l49C. a test strip which only containsthe additives C and B serving as comparison. In these tests, 3 teststrips of each formulation are employed. The end point is defined as theincipient easily visible decomposition of the test strip and the resultsare quoted in days.

Table 9 Stabiiiser No. Days to incipient Decomposition without 1additive90 20 IS NO 2i Comparison Products EXAMPLE 14 a. Manufacture of the TestSpecimens parts by weight of unstabilised polybutene-l in the fonn of apowder aare thoroughly mixed in a shaking apparatus with 0.1 part byweight of B-(3,5-di-tert.- butyl-.4-hydroxyphenyl)-propionic acidoctadecyl ester, 0.3 part'by weight of dilaurylthiodipropionate and 0.5part by weight of Stabiiiser No. 10.

This mixture is plasticised and homogenised for l0 minutes in aBrabender plastograph at 200C, at the end of this time 1 part by weightof powdered copper (manufactured electrolytically, Merck) is added andthe whole is then mixed for a further 2 minutes at the same temperature.The resulting mass is pressed in a sheet press at 220C platentemperature for 6 minutes to give 1 mm thick sheets and test strips l cmwide and 14 cm long are punched therefrom. The test specimens withoutadded copper, required" for comparison purposes, are manufacturedanalogously.

b. Test The test of the activity of the metal deactivator added to thetest specimens containing copper is carried out by heat aging in acirculating air oven at C up to the first sign of incipientdecomposition of the test specimen. 3 test specimens are employed foreach formulation, and their oven lives are determined.

in these tests, the test specimens which contain Stabiiiser 10 as yetshow no sign of decomposition at a point in time where the unstabilisedtest specimens are already completely decomposed.

EXAMPLE i5 tort lulyi-@- CONHNHCO-C H 7.7 g (0.04 mol) of4-tert.-butyl-benzoic acid hydrazide are dissolved in 60 ml ofdimethylacetamide. A solution of 8.7 g (0.04 mol) of lauric acidchloride in 40 ml of dimethylacetamide is slowly added dropwise at roomtemperature. Thereafter 4.0 g of triethylaminc are added to the solutionand the mixture is stirred for l hour at 60C. After cooling. the mixtureis poured into 1 litre of water and the product which has precipitatedis filtered off and directly recrystallised from ethanol.N-p-tert.butylbenzoyl-N'-benzoyl-hydrazine (Stabiiiser No. 28) ofmelting point 100C is thus obtained.

if, in this example, the lauric acid chloride is replaced by anequimolecular amount of stearic acid chloride and otherwise the sameprocedure is followed, N-ptert.-butylbenzoyl-N'-stearoyl-hydrazine(Stabiiiser No. 29) of melting point lO6C is obtained.

We claim:

I. A composition of matter stabilised against thermooxidativedegradation and discoloration which comprises a polyolefin and a. from0.0l to 5 percent by weight of a compound A of the formula wherein R,and R, independently of one another denote the unsubstituted phenylgroup, a phenyl group substituted by a hydroxyl group in the morp-position.

by one or two alkyl groups each with l to 4 carbon atoms, by one or twoalkenyl groups each with 3 or 4 carbon atoms, by one or two cycloalkylgroups with 6 to 8 carbon atoms, by l or 2 chlorine atoms, by one or twoalkoxy groups each with l to 18 carbon atoms or by an acylamino groupwith 2 to 18 carbon atoms or by an amino group in the oposition, orwhere R also denotes hydrogen, alkyl with l to 18 carbon atoms,cyclohexyl or benzyl if R, denotes a substituted phenyl group, and

b. 0.3 percent by weight of an ester of B-thiodipropionic acid selectedfrom the group consisting of dilauryl B-thiodipropionate and distearylB-thiodipropionate.

2. A composition according to claim 1 containing compound A wherein R,and R, independently of one another denote a phenyl group substituted bya hydroxyl group in the mor p-position, by one or two alkoxy groups eachwith l to 18 carbon atoms, by an acylamino group with 2 to 7 carbonatoms or by an amino group in the o-position, or where R, also denotesalkyl with l to 8 carbon atoms, benzyl or phenyl if R, represents anacylaminophenyl group with 2 to 7 carbon atoms in the acyl radical.

3. A composition according to claim 1 containing compound A wherein R,and R, independently of one another denote a phenyl group substituted bya hydroxyl group in the mor p-position, by one or two alkoxy groups eachwith l to 16 carbon atoms, by an acylamino group with 2 to 7 atoms or byan amino group in the position, or where R, also denotes methyl orphenyl it"R, represents an acylaminophenyl group with 2 to 7 carbonatoms in the acyl radical.

4. A composition according to claim 1 in which compound A is present ina concentration of from 0.05 to L percent by weight.

5. A composition according to claim I in which compound A is present ina concentration of from 0.1 to 0.8 percent by weight.

6. A composition according to claim 1 in which the polyolefln ispolypropylene.

7. A composition according to claim 1 in which compound A is cn o ocncommuco cn o ocu 8. A composition according to claim 1 in which compoundA is 9. A composition according to claim 1 in which compound A is 10. Acomposition according to claim 1 in which compouund A is NH: an,g-commnco 11. A composition according to claim 1 in which compound A isCl'l CONH- CONHNHCOCH

1. A COMPOSITION OF MATTER STABLISED AGAINST THERMOOXIDATIVE DEGRADATIONAND DISCOLORATION WHICH COMPRISES A POLYOLEFIN AND A. FROM 0.01 TO 5PERCENT BY WEIGHT OF A COMPOUND A OF THE FORMULA
 2. A compositionaccording to claim 1 containing compound A wherein R1 and R2independently of one another denote a phenyl group substituted by ahydroxyl group in the m- or p-position, by one or two alkoxy groups eachwith 1 to 18 carbon atoms, by an acylamino group with 2 to 7 carbonatoms or by an amino group in the o-position, or where R2 also denotesalkyl with 1 to 8 carbon atoms, benzyl or phenyl if R1 represents anacylaminophenyl group with 2 to 7 carbon atoms in the acyl radical.
 3. Acomposition according to claim 1 containing compound A wherein R1 and R2independently of one another denote a phenyl group substituted by ahydroxyl group in the m- or p-position, by one or two alkoxy groups eachwith 1 to 16 carbon atoms, by an acylamino group with 2 to 7 atoms or byan amino group in the o-position, or where R2 also denotes mEthyl orphenyl if R1 represents an acylaminophenyl group with 2 to 7 carbonatoms in the acyl radical.
 4. A composition according to claim 1 inwhich compound A is present in a concentration of from 0.05 to 1.5percent by weight.
 5. A composition according to claim 1 in whichcompound A is present in a concentration of from 0.1 to 0.8 percent byweight.
 6. A composition according to claim 1 in which the polyolefin ispolypropylene.
 7. A composition according to claim 1 in which compound Ais
 8. A composition according to claim 1 in which compound A is
 9. Acomposition according to claim 1 in which compound A is
 10. Acomposition according to claim 1 in which compouund A is
 11. Acomposition according to claim 1 in which compound A is
 12. Acomposition according to claim 1 containing additionally from 0 to 0.1percent by weight of a phenolic antioxidant.
 13. A composition accordingto claim 12 containing a phenolic antioxidant selected from the groupconsisting of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acidoctadecyl ester and1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane.